On the way home...

You're driving the mostly empty streets between campus and home. Sara is sitting next to you, illuminated by the glow from her phone screen.

"Sara?"

"...Yeah?"

"What's... what's going on?"

"What do you mean?"

"This is now the second time you've insisted on, uh... having help? getting your medicine."

"Yeah."

"So... why?"

"Because... it's fun?"

You nod.

"Yeah. It is. It is fun, I'm not going to sit here and say it's not fun. But, what am I supposed to do? I'm in love with your sister."

"Don't make this about you! I'm the one with a disease!" She huffs and goes back into her phone.

You pull into the parking lot of a closed supermarket and park. You cut the engine.

"I'm not attacking you, Sara."

She turns to face you again. You can't help but look down her top.

"You're, like, blaming me for you cheating on Nikki, or whatever. But, like, you weren't complaining when you were balls deep in Alicia's asshole! Besides, you're not even cheating! Nikki ASKED you to be my provider. She WANTS you to. And part of you providing my medicine is you doing it the way I want. Right?"

"...Right."

"So... I want threesomes. I like them. It's fun. It makes... I don't know, it makes having the disease, like, not so bad."

"I can't keep fucking other girls."

"Right. Just me and Alicia and Jenny."

"I shouldn't have done that. It's already gotten out of control. I don't want to hurt your sister."

"John... just, like, tell Nikki? Like, tell your girlfriend that I want to get my medicine in threesomes sometimes. I don't think it's going to be a big deal for her. Did you already forget dinner? She fingered herself while watching you fuck me. She's into you fucking other girls. She's totally a cuckquean."

"Yeah, I guess she is."

"She totally is. She's totally getting off on you fucking me. God, I had no idea Nikki was such a slut."

"What about you?"

"Oh, I already knew I was a slut."

"I thought you were a virgin before you moved in with us."

"I was... But I also knew for a long time that I wanted you to pop my cherry."

"Really?" you smirk.

"Ever since that first time Nikki brought you home for dinner. You were just... I had the biggest crush on you, like, ever. God, I'd rub my pussy thinking about you every night. Most mornings. Every time I took a shower." She bites her lip. You can see her nipples getting hard under the thin material of her tank top. She rubs her thighs together.

"You'd think about me when you touhed yourself?"

She nods.

"I'd rub my little pussy and imagine it was you touching me. I'd pretend that I ran into you at the mall and you were shopping for a gift for Nikki, so you took me into a changing room and had me model sexy clothes for you. Or that you walked in on me in the shower expecting Nikki, but then you stayed and got in with me. Or I'd pretend that Nikki got called in to work and you came over to see her, but instead of leaving when you saw she wasn't here, you came inside and we watched a movie together. I'd do my makeup and put on my shortest skirt and then I'd pretend my hand was your hand sliding up my thigh. I'd finger myself and imagine you were taking advantage of me. Making me suck you. Making me fuck you. Making me be your secret little whore. You'd call me 'slut' and say 'I know how much you wanted this'."

"Every night?"

She nods.

"Up to and including tonight," she opens the button on her shorts and works a hand inside. "I've wanted to be your slut for forever."

You unzip your fly, pulling out your growing erection.

"Come here," you say. "Slut."

Sara moans, and then repositions herself so she's kneeling on her seat, rubbing her pussy with one hand while her mouth closes around the head of your cock.

"Yeah," she breathes. "I am your slut."

She sucks you into her hot mouth and your head lolls back.

"Fuck," she gasps when she comes up for air. "Your dick still tastes like Jenny's cunt."

"Shut up and suck my cock, slut."

She moans and takes you back down her throat.

"This is what you've always wanted, slut. Now you've got it. My cock down your fucking throat. How's it feel? Being my little cumslut? Literally living for my cum? I know how much you wanted this."

Her hand is moving rapidly inside her shorts and the way she moans around your cock sends vibrations down through your balls.

You feel yourself getting close, and slip a hand inside her shirt and twist her nipple right as you pop.

The two of you cum at the same time. Sara in her pants, and you down her eager throat. She sucks and sucks at your cock even after you've finished pumping your load into her. Her sucks slow in intensity and you start to soften, but she still continues. She's not really "sucking your dick" anymore. She's worshiping it.

"Fuuuuuuck," you moan. "Oh, god... you've gotta stop or you're gonna get me hard again."

She doesn't stop.

She starts sucking harder. You close your eyes, lost in the feeling.

"Ohhhh, shit, Sara... that's so fucking gooood..."

*TAP TAP TAP*

You open your eyes and see a flashlight pointed in your face.

"Oh shit! Sara! Cops!

"Step out of the car please?" comes muffled through the window.